A real-time locating system (RTLS) is a system which checks the location of people or objects in real-time based on a specific technique using radio frequency identification (RFID) or a wireless LAN, and may be used in various fields.
In general, the RTLS technique includes an RTLS transmitter, e.g., an RFID tag which is attached to each object, and an RTLS receiver, e.g., an RFID reader which reads an identifier of the object having the RFID transmitter in a wireless communication. The RTLS technique provides a position service of an object by collecting, storing and processing the object information, and tracking the object. The RTLS receiver recognizes the position of the RTLS transmitter based on position information including intensity, a receiving time and a receiving direction of a signal transmitted from the RTLS transmitter.
However, although it is requested that a clock of the RTLS receiver is synchronized to a precise standard time in order to recognize the position of the RTLS transmitter, the clock synchronization technique is not provided within an error range of a nano-unit.
Accordingly, it is necessary to provide a method for synchronizing a clock into a highly precise standard time having an error range of a nano-unit through each reader which receives clock information from a clock synchronization server.